Dying for a kauri solution

Te Roroa spokesman Will Ngakuru with Tane Mahuta, the 1,500-year-old kauri in Waipoua Forest. Photo / NZME.

Six years after the mystery killer of our beloved native tree was identified, agencies are still scrambling to contain its spread. Geoff Cumming reports

You don't have to look far in the Waipoua Forest to see signs of stress - nor signs that fail to do the job of protecting its world-renowned kauri stands from human folly.

From high above the forest at the old fire lookout, telltale signs of kauri dieback disease - withered branches, denuded of leaves - splay like witches fingers from the olive green canopy. Up close, disfiguring lesions and bleeding sap around the base of trunks signify infection.

Once the soil-borne microbes - a kauri-specific strain of phytophthora - infiltrate the roots, it's just a matter of time before these northern native forest kings succumb.

Diseased trees, for now, are a small minority - though it can take years for symptoms to show. It's worse in the Waitakeres where 11 per cent of kauri are diseased.

In the worst case scenario, scientists portray a future where our grandchildren can no longer go into the bush to admire these slow-growing giants (all that's left of a kauri harvesting frenzy from the late-19th century) and the ecosystems they support.

It's now thought the disease spread unchecked for 50 years before scientists isolated the new phytophthora in 2008 - the disease's slow progression in mature trees helping to explain why agencies are only now coming to terms with how far it has spread and confirming "new" areas of infestation.

"Nothing happens quickly in the kauri world," says Plant and Food scientist Dr Ian Horner, who is researching the use of a chemical injection which promises to delay the disease's progress in infected trees.

That's probably just as well because since the phytophthora was identified, authorities have struggled to muster a best-practice response.

That verdict may be harsh - a lot has been achieved in six years: Auckland Council track closures in the Waitakeres seem to be thwarting the spread of phytophthora and visitors are increasingly following hygiene protocols at track cleaning stations.

Increased Government funding is helping scientists to research short and long-term responses (see story below).

At community level, interest groups are joining forces to fight back: standout examples include the Coromandel Kauri Dieback Forum, which is co-ordinating awareness campaigns and surveillance work, and the Waitakere local board, which has found $45,000 to put a person on the ground to co-ordinate education.

Forest track closures, though unpopular and hard to enforce, may prove most effective in stopping the spread of the disease in both infected and uninfected areas. Philanthropic groups such as the Tindall Foundation are offering funding for farmers to fence off stands on private land.

The 150ft Tane Mahuta kauri tree is the 'lord of the forest'.

A symposium this weekend, on the Hokianga Harbour near Waipoua, will rightly acknowledge such progress and showcase the scientific lines of inquiry. But it takes place against a backdrop of frustration among those seeking action.

They include trampers, greenies, pig hunters, iwi, farmers and other private landowners - those with infected stands and those who want to keep the disease out - all seeking techniques, tools and information to fight the disease.

"The frustration is palpable and it's coming from all areas," says Ian Mitchell, relationship manager for the Kauri Dieback Management Programme. "Communities want to see results because millions of dollars are being poured into this response."

Impatience stems in part from European expectations that science will quickly find a cure for new biosecurity threats. None is in sight. "Science can't come up with quick answers - we may never eliminate this disease," Mitchell says.

While scientists work to understand the phytophthora and develop possible responses, Mitchell's best bet is to change the behaviour of forest users. "That's my biggest challenge." Along with pigs and cattle, humans are major culprits in spreading soils containing the disease - bush walkers, mountain bikers, pig hunters, forest contractors, farmers, their equipment and their vehicles.

The kauri's status is such that most people, including tourists, are keen to help when made aware of the problem. But the biosecurity response could do better.

There is dismay that the disease has spread to the Coromandel Peninsula, thought phytophthora-free until a year ago. It was hoped the discoveries near Whangapoua and inland from Whitianga were isolated cases, but tests have just confirmed the infestation near Whangapoua is much more widespread than thought.

Beyond those in the frontline, there's still some complacency: the disease's slow progression means people underestimate the threat.

Detection, particularly soil sampling, is costly - so areas thought disease-free, such as the Hunuas, may yet have infected trees.

The plethora of agencies involved complicates the response: the web of responsibilities and funding streams embraces DoC, iwi, three regional councils, three Crown research agencies, universities, the Ministry for Primary Industries, even the Ministry for Business, Innovation and Employment.

There is criticism of DoC's reduced on-the-ground presence, for both surveillance and education, after years of restructuring and budget cuts. The current centralisation and splitting of functions is just the latest upheaval.

But infected kauri are not confined to the conservation estate. Regional councils, which administer parks and are supposed to help private landowners, are under severe budget constraints and kauri dieback initiatives are in the firing line.

Waikato's sole dedicated kauri dieback staffer faces redundancy. Auckland Council's budget for kauri dieback in its new 10-year plan was on the chopping block until lobbyists intervened.

Some of this may be no worse than bureaucratic wheels taking time to move. Those questioning what DoC is doing with $21 million in new funding allocated over four years may have missed that $10 million for capital works doesn't kick in until July this year.

Given the disease's slow pace of progression, that may be okay. DoC has used the delay to prioritise which high-use areas to install boardwalks and upgrade tracks; $10 million won't cover the lot.

Mitchell's umbrella group has brought most players, and regions, on to the same page - though he agrees it's like herding cats. In December a national strategy was unveiled. But overarching strategies and head office reports fail to capture daily realities in the bush.

At the Waipoua River bridge, across the road from the visitor centre turnoff, DoC - only after considerable pressure - has closed the Rickers Track where a popular kauri stand is badly infected.

But the track is still promoted in DoC material and the closure is enforced by no more than a roll of "warning" tape at the entrance. The tape proved no barrier to summer visitors who then inspect other kauri stands, potentially spreading the disease.

Along the road, DoC relies on visitors to Tane Mahuta keeping to its upgraded boardwalks. The disease has crept to within 120m of our most famous tree but, at 1500 years, it appears in rude health.

There is just one hygiene station in the Waipoua where visitors can clean their boots and spray on Trigene disinfectant, at the entrance to tracks leading to Te Matua Ngahere and other drawcard kauri.

It's a bottleneck - visitor numbers are such that queues regularly form both ways and patience wears thin. While most try to comply with the boot-cleaning regime, few understand to brush the mud off their boots before squirting on the disinfectant.

Such micro-level glitches would appear easily fixed but signage is lacking and there's no one on the ground to educate or report back to HQ, with potentially lethal consequences. DoC says it is working on improved cleaning station design and signage.

The Te Roroa iwi want a more hands-on role in governance of Waipoua, their spiritual and cultural lifeblood. Already, they are managing road maintenance contracts and have a co-management role with DoC under their 2008 treaty settlement.

But negotiations to declare Waipoua a national park have been on hold since before last year's election.

Spokesman Will Ngakuru says the Government seems wary of a political backlash if it hands over conservation estate to iwi. The iwi wants all parties with a relationship with the forest - adjacent forestry companies and farmers, DoC, iwi, forest visitors and the tourism industry - to adopt an integrated management approach. "Some players struggle to understand what we are seeking," Ngakuru says.

Incoming Conservation Minister Maggie Barry says she is strongly committed to the national park proposal and kauri dieback has added urgency. She regrets the post-election delay.

Until such issues are resolved, and until science comes up with alternatives, it would seem the best response lies in individual responsibility.

"It's human nature to want answers, but there are no definitive answers," says Coromandel forum chairwoman Vivienne McLean.

"It's frustrating - we would like to see more being done but DoC is still under financial constraints and going through restructuring.

"Bush users need to accept there won't be cleaning stations at every track.

"The key thing is to remove dirt from boots - Trigene [disinfectant] isn't enough. We have to change the way we engage with the bush, not just recreational users but forestry contractors, farmers, people doing pest management ...

"It should become part of our psyche: you go into the forest with clean equipment and you clean it again when you come out.

"And if certain forests have to close, we'll just have to live with that."

- The 2015 Kauri Dieback Symposium is at the Copthorne Hokianga today with a field trip to Waipoua Forest tomorrow.

Injections help slow disease's advance

Dr Ian Horner injects phosphite into kauri.

A fungicide widely used to combat phytophthora-type diseases in crops shows promise in helping infected trees withstand kauri dieback.

While no cure is in sight, scientists hope phosphite injections will help slow the advance of symptoms in infected trees and help them live for longer.

Phosphite sprays have long been used to treat diseases in avocados and potatoes.

Plant and Food scientist Dr Ian Horner said trials at four infected sites in Auckland and Northland forests showed phosphite slowed the progression of the disease.

The chemical might also help to slow or stop the spread of the soil-borne disease through root growth to nearby trees.

But moving from field trials to mass-treatment is still several years away, frustrating landowners seeking effective tools to fight the disease.

The five-year trial is entering its third year. More time is needed to research dosages and ensure the chemical does no long-term harm.

"I'm confident we will get to a treatment regime which on balance will be beneficial, but we are not quite there yet," Horner said.

The science response by Plant and Food, forest research agency Scion and Landcare Research has been boosted by new Government funding under the joint Healthy Trees, Healthy Future programme.

Landcare scientists are studying the disease's behaviour, understanding why some trees withstand the disease better than others, and looking for better detection tools.

Scion is focusing on breeding phytophthora-resistant strains of kauri to replace diseased trees - a very long-term solution. University researchers are also involved.

"We've got to start this work, otherwise our grandchildren won't thank us," Horner said. "You get a stand of infected trees and all you can do is sit and see it kill infected trees and spread into others."

Meantime, the best response was to contain the disease's spread.